Module 8 - Chemical Equations V5

Question 1

What separates individual reactants and products in a chemical equation?

Answer 1

a plus sign

Question 2

A product is a substance which is generated as a result of a chemical reaction.

Answer 2

true

Question 3

Chemical equations refer to the written form of a chemical reaction.

Answer 3

true

Question 4

The formula mass of a compound is the sum of the atomic weights of each element in its chemical formula.

Answer 4

true

Question 5

What information is not needed to calculate percent composition?

Answer 5

the state of matter of the compound

Question 6

The molecular mass applies to ionic compounds.

Answer 6

false

Question 7

Coefficients refer to the amount of a specific atom.

Answer 7

false

Question 8

What is the balancing coefficient of O2 in the following equation?

CH4(g) + ?O2(g) → CO2(g) + H2O(l)

Answer 8

2

Question 9

An equation is balanced when both the reactant side and the product side of the reaction have unequal numbers of each type of atom.

Answer 9

false

Question 10

Atomic mass and molecular mass have the same units.

Answer 10

false

Question 11

The molar mass is the mass of one mole of a given substance.

Answer 11

true

Question 12

What are the units of molar mass?

Answer 12

g/mol

Question 13

A + BX → B + AX is the general formula for a single replacement reaction.

Answer 13

true

Question 14

Decomposition reactions occur when an element which is more reactive takes the place of one which is less reactive, thus resulting in two new compounds.

Answer 14

false

Question 15

Predict the products of the following combination reaction.

C(s) + O2 →

Answer 15

CO2

Question 16

Which is not a type of yield?

Answer 16

limiting reactant

Question 17

The actual yield is the actual amount of product obtained from a chemical equation.

Answer 17

true

Question 18

The limiting reactant is the reactant which is not consumed.

Answer 18

false

Question 19

Every chemical reaction will have __________ and __________.

Answer 19

reactants; products

Question 20

Chemical equations always include an arrow signifying what?

Answer 20

the direction of the reaction.

Question 21

Coefficients can be represented as…

Answer 21

whole numbers.

Question 22

The state of matter is never included in chemical equations.

Answer 22

false

Question 23

Glass is a common material used for windows and screens and can be created from silicon dioxide, SiO2. What is the formula mass of silicon dioxide?

Answer 23

60.06amu

Question 24

Aspirin is a common medicine to treat pain relief related to issues such as headaches and toothaches. The chemical formula for aspirin is C9H8O4. What is the most accurate percent composition of carbon in aspirin?

Answer 24

60%

Question 25

Potassium oxide (K2O) is often used in agriculture as a fertilizer. Which represents a balanced chemical equation for producing potassium oxide?

Answer 25

4K + O2 → 2K2O

Question 26

Incomplete combustion happens when there is an insufficient supply of air. This is dangerous because it produces carbon monoxide, or CO, a poisonous gas. What is the balancing coefficient for carbon monoxide in the incomplete combustion of propane gas?

2 C subscript 3 H subscript 8 plus 9 O subscript 2 rightwards arrow 4 C O subscript 2 plus ? C O plus 8 H subscript 2 O plus H e a t

Answer 26

2

Question 27

The __________ is a unit of measure for the number of atoms in a sample.

Answer 27

mole

Question 28

One mole is equivalent to…

Answer 28

6.022 x 1023 atoms.

Question 29

Hydrogen and oxygen (O2) react to form liquid water. If there are 10 grams of oxygen reacting with hydrogen, how many moles of oxygen would be in the resulting water product?

Answer 29

0.31 moles

Question 30

Hydrochloric acid (HCl) is intense and can burn through materials as a component used in batteries and fireworks. The balanced equation for the production of hydrochloric acid is:

H subscript 2 plus C l subscript 2 rightwards arrow 2 H C l

How many molecules of HCl are produced from 0.35mol of H2?

Answer 30

4.2 x 1023 molecules

Question 31

__________ reactions occur when a single reactant breaks into multiple products.

Answer 31

decomposition

Question 32

B a C l subscript 2 left parenthesis a q right parenthesis plus N a subscript 2 S O subscript 4 left parenthesis a q right parenthesis rightwards arrow B a S O subscript 4 left parenthesis s right parenthesis plus 2 N a C l left parenthesis a q right parenthesis
This is an example of a __________ reaction.

Answer 32

double replacement

Question 33

Combustion reactions always produce…

Answer 33

carbon dioxide and water.

Question 34

What are the products in a reaction between copper (Cu) and silver nitrate (AgNO3)?

C u plus 2 A g N O subscript 3

Answer 34

2Ag + Cu(NO3)2

Question 35

When a reaction produces a single product, a __________ reaction has occurred.

Answer 35

combination

Question 36

If there are 5 moles of sodium and 8 moles of chlorine reacting to create table salt, NaCl, what is the limiting reactant?

2 N a open parentheses s close parentheses plus C l subscript 2 open parentheses g close parentheses rightwards arrow 2 N a C l open parentheses s close parentheses

Answer 36

Na

Question 37

A solution of nickel sulfide (NiS) with a mass of 8.5g was created using 4.4g of nickel and excess of sulfur. Calculate the theoretical yield of NiS.

S plus N i rightwards arrow N i S

Answer 37

6.8g NiS

Question 38

Calcium carbonate decomposes into calcium oxide and carbon dioxide. What is the percent yield if a sample of calcium carbonate with a mass of 38g yields 20g of carbon dioxide?

CaCO subscript 3 rightwards arrow CaO plus CO subscript 2

Answer 38

83%